Myelination of axons is essential for the normal function of the vertebrate central nervous system (CNS), and is a multi-step process that requires oligodendrocyte precursor cells (OPCs) to recognize target axons and differentiate into myelinating cells. Although myelination occurs primarily in early postnatal life, it can be re- initiated in adult CNS in response to demyelinating injury. This remyelination process is, however, limited in demyelinating diseases such as multiple sclerosis, in part due to the failure of OPCs to differentiate into mature oligodendrocytes. As remyelination promotes axonal survival and functional recovery, how to coax OPCs to differentiate into myelinating cells represents a critical step in achieving myelin repair and functional recovery. Currently, there is no clinic therapy aimed at promoting myelin repair. Thus, the goal of this proposal is to identify small molecules that promote OPCs to differentiate into myelinating cells. We will employ a novel CNS myelinating culture system recently established in our laboratory to screen a chemical library consisting of 200,000-drug-like compounds. To achieve high throughput and direct visualization of oligodendrocyte maturation, we will use cultures derived from our newly generated transgenic mice where membrane-anchored enhanced green fluorescence protein is selectively expressed in myelin sheaths and mature oligodendrocytes. Lead compounds identified by chemical screening will then be tested in culture for their efficacy in promoting OPCs into myelinating cells and in an animal model of demyelination. This proposed study has the potential to lead to the development of novel therapeutic interventions aimed at promoting myelin regeneration and functional recovery.